Process–structure–property relationship for plasma-sprayed iron-based amorphous/crystalline composite coatings

This study explores the fabrication of Fe-based amorphous/crystalline coating by air plasma spraying and its dependency on the coating parameters (plasma power, primary gas flow rate, powder feed rate, and stand-off distance). X-ray diffraction of the coatings deposited at optimized spray parameters showed the presence of amorphous/crystalline phase. Coatings deposited at a lower plasma power and highest gas flow rate exhibited better density, hardness, and wear resistance. All coatings demonstrated equally good resistance against the corrosive environment (3.5wt% NaCl solution). Mechanical, wear, and tribological studies indicated that a single process parameter optimization cannot provide good coating performance; instead, all process parameters have a unique role in defining better properties for the coating by controlling the in-flight particle temperature and velocity profile, followed by the cooling pattern of molten droplet before impingement on the substrate.